原创 使用输入捕捉的信号周期测量(带数码管显示)

/********************************************************
Project              :使用输入捕捉的信号周期测量
Chip type            :ATmega8L (VCC=3V)
Clock frequency      :8.000000 MHz
Author               :
Edition              :V1.0
Time                 :2008.06.02
Comments             :
    能正常的测量及显示,但误差较大
********************************************************/
#include <iom8v.h>
#include <macros.h>
#include "selffile.h"

#pragma data:code
const unsigned char table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f, 
                             0x77,0x7c,0x39,0x5e,0x79,0x71};  //七段译码字型表(共阴极)
#pragma data:data
unsigned char ledbuff[8];
unsigned int  oldcount,newcount;


void  main(void)
{
    mcu_init();                      //MCU初始化
        led_display(0);                  //LED初始显示0
        delay_nms(1000);
        while(1)
        {
            if(newcount!=oldcount)      
                   oldcount=newcount;        //捕捉到新的数值则更新显示
        
                led_display(oldcount);
                delay_nms(1000);
        }
}

void  mcu_init(void)
{
    CLI();
    DDRB&=~(1<<PB0);                //捕捉IO口为输入
        DDRC|=(1<<PC4)|(1<<PC5);        //LED-DATA、CLK为输出
        DDRD|=(1<<PD4);
        PORTB=0x00;
        PORTC=0x00;
        PORTD=0xff;
        TIMSK=0x20;                     //使能T1捕捉中断
        ICR1=0;
        TCNT1=0;
        TCCR1A=0x00;
        TCCR1B=0xC1;                    //不分频,用8M进行采样,更准确,但有4K左右的误差
        SEI();
}

void  hextobcd(unsigned int Icp_count)
{
    unsigned char i,temp;
        for(i=0;i<4;i++)
        {
             temp=Icp_count%10;
                 ledbuff=table[temp];
                 Icp_count=Icp_count/10;
        }
}

void  led_display(unsigned int DData)
{
    unsigned char i,j;
        unsigned int  Icp_data=0;

    hextobcd(DData);
        
        for(i=0;i<4;i++)                       //采用移位寄存器HC164实现串入并出
        {
                 for(j=0;j<8;j++)
                 {
                      PORTC_LED_CLK_0;
                      if((ledbuff&0x80)==0x80)
                              PORTC_LED_DATA_1;
                          else
                              PORTC_LED_DATA_0;
                          
                          PORTC_LED_CLK_1;
                          ledbuff=ledbuff<<1;
                 }                          //在此循环后无须加延时,否则会造成明显的闪动
         }
}

void  delay_nms(unsigned int n)          //延时n ms
{
    unsigned int i;
    for(i=0;i<n;i++)
           delay_1ms();
}
void  delay_1ms(void)                    //8M.延时1ms
{
    unsigned int i;
        for(i=1;i<1142;i++)
        ;
}

#pragma interrupt_handler Icp_timer1:6
void  Icp_timer1(void)                  //捕捉中断
{
    newcount=ICR1;
        ICR1=0;
        TCNT1=0;
        TCCR1B=0xC1;
        PORTD&=~(1<<PD4);                   //指示灯亮
}